TITLE: Racism, Residential Racial Segregation, and Breast Cancer Survival Disparities among Black, Hispanic and non-Hispanic White Women ABSTRACT/SUMMARY Racial disparities in breast cancer survival are significant, with only 68% of US Black women diagnosed with breast cancer remaining alive 10 years post-diagnosis, compared to 84% of White women. However, the size of the racial disparity in breast cancer mortality varies geographically across the US, from no observable state- level disparity between Black and White women in Minnesota and Massachusetts, to a mortality rate ratio of over 1.60 in Mississippi, Louisiana, and Wisconsin. Further, although the national survival gap between Hispanics and non-Hispanic Whites is small, national numbers mask substantial variation among subpopulations of Hispanics and poorer outcomes among Hispanics in some localities. Such geographical variation suggests that disparities are not inevitable, and this variation has not been explained. Racism and racial residential segregation are widely considered to contribute to health disparities, and may partially explain geographical variation in the size of the disparity. While some studies have shown that segregation is related to poor survival, others have found that this is not always the case, and some studies highlight the case of ethnic enclaves, which may be protective. Additionally, we have recently shown that a measure of racial bias in housing is associated with breast cancer survival among Black women in the Milwaukee area. We propose to build upon our previous work to undertake a national study of segregation and breast cancer survival with three aims: (1) Construct new and existing metrics of racism and segregation at the local level for the largest US metropolitan areas, and determine (a) how measures co-vary, (b) whether segregation measures predict stressors, social resources and opportunities at the local level, and (c) whether relationships differ by metropolitan area, (2) Determine whether measures of segregation are related to breast cancer survival disparities among Black, Hispanic and Non-Hispanic White women, and whether relationships are mediated by local stressors, social resources, or opportunities, and (3) Explore the ways in which Black and Hispanic breast cancer survivors in a highly segregated metropolitan area navigate cancer survivorship in the context of segregation. The interdisciplinary research team is well-positioned to conduct this work, with expertise in breast cancer, health disparities, geography, biostatistics, epidemiology, large database analysis, mediation analysis, qualitative research, and community engaged research. Further, we have established partnerships with numerous local community organizations working directly with breast cancer survivors in the Milwaukee area through a regional community advisory board, and have drawn upon these relationships to convene an advisory board specific to this project, engaged to guide and support data collection and interpret and disseminate research findings. The successful completion of the proposed work will support the development of future multi-sectoral interventions to reduce disparities by targeting local systems and policies.